1. Technical Field
The present invention relates to a technique for performing printing on a printing medium.
2. Related Art
In the related art, a serial printing apparatus is known that performs printing on a printing medium by moving a print head relative to the printing medium in a main scanning direction and a sub-scanning direction. The print head has arrays of nozzles that are arranged in the main scanning direction so as to eject ink of each color (see JP-A-2007-145031). For example, when a nozzle array for ejecting yellow ink and a nozzle array for ejecting black ink are arranged in the print head in that order in the main scanning direction, the yellow ink will be ejected earlier than the black ink when seen from the same printing position.
When another ink is ejected at the same printing position, the ink ejected later may bleed depending on the dryness level of the ink ejected earlier. Therefore, if the later-ejected ink is an ink that is easily noticeable because of its lower brightness than the earlier-ejected ink, the bleeding of ink will be more easily noticeable. Moreover, if the earlier-ejected ink mixes well with a later-ejected ink, the later-ejected ink will bleed more easily.
Such a problem becomes particularly prominent in the case of bidirectional printing where ink is ejected for both the forward path and the return path of the print head (see JP-A-2007-145031). Since the bidirectional printing changes the order of the inks ejected, the likelihood of bleeding changes, and thus there is a concern that non-uniform density may occur even when the same color is formed for the forward path and the return path.